The Paris Agreement had a clause where it only comes to force if enough countries ratify it:

The Paris Agreement entered into force on 4 November 2016, thirty days after the date on which at least 55 Parties to the Convention accounting in total for at least an estimated 55 % of the total global greenhouse gas emissions have deposited their instruments of ratification, acceptance, approval or accession with the Depositary.

However there aren't any clauses around automatic termination in the event that countries representing 55% of global emissions fail to meet their commitments. This creates a game theory problem - if countries like Norway scale down their economy to meet their greenhouse emission goals but China does the opposite, Norway's efforts would've all been pointless in the end as China's emissions will still heavily contribute to climate change. So why aren't these agreements written in a way where countries only promise to make changes as long as everyone does them at the same time? Surely Norway would want stronger commitments from China or the US before harming their own economy in any way?


3 Answers 3


As noted in the question, climate negotiations are susceptible to bad actors, and nations might not be willing or able to deliver on the necessary changes to meet their agreed targets.

You're basically asking, "If the world's going to end anyway, why not hasten it along and make sure you get yours?"

Adding a self-termination clause to a fatal state is redundant. The agreement will already self-terminate when climate change has inflicted sufficient damage that international relations are largely irrelevant.

Until that point in time, there remains time to do something about it. And a self-termination clause could erase whatever (inadequate) efforts were trying to stave that point off.

The dominant strategy in a once-off prisoner's dilemma is betrayal, resulting in the worst-case scenario for both parties.

Knowing this, there's a powerful incentive to avoid setting up that game in the first place. Instead, what you want, is a game where people who think they're playing Prisoner's Dilemma are given as much time as possible to realize their mistake and start playing Survive Climate Change instead. That means leaving in place whatever commitments to mitigate climate change can be managed, and using the good-faith performance of some signatories as a leverage point against those nations that underperform.

Self-terminating those agreements, instead, hastens the worst-case end state and cuts short the window for avoiding it.


This is precisely because of free rider problems. Ultimately we only have one world to inhabit and only one chance to get it right.

This is a somewhat different condition from normal market conditions where there is usually a chance to restart. Also, unlike a normal market, participants are all sovereign nations, with no real way to enforce behavior.

If the actions of any set of actors triggered abandonment then we would be back at square one, having run down the clock a bit more. This is precisely what we want to avoid.

Early game theory such as the prisoner dilemma focussed on zero-sum game, one-off situations. They are hugely influential in decision analysis, but additional studies in the field have also looked at recurring events, where actors gradually can gravitate towards more collaborative behavior.

The experimental data show that cooperation is affected by infinite repetition and is more likely to arise when it can be supported in equilibrium. However, the fact that cooperation can be supported in equilibrium does not imply that most subjects will cooperate. High cooperation rates will emerge only when the parameters of the repeated game are such that cooperation is very robust to strategic uncertainty.

In this case far better to name and shame the shirkers on the next round. Reality is we are still learning how to collaborate on this problem, with many actors having differing priorities but still mostly being faced with negative outcomes if we get it wrong enough (for example, the Arabian Gulf states may want to export gas as long as possible but their geographic area is also projected to start hitting human wet bulb heat tolerance limits).

As opposed to Kyoto (1992) one of the new approaches since Paris (2015) has been ratchets or NDC (nationally determined contributions). Rather than committing all at once to "fixing everything" like they did before, nations commit to self-chosen goals to limit emissions, which are then expected to strengthen every 5 years. This gives them opportunities to get back in shape, without just throwing up their hands (as Canada did from as soon as it signed Kyoto, for example). And since these are self-chosen, they are hopefully more likely to be followed up on, building trust amongst the actors.

Note: as remarked upon in the comments, the most famous game theory problem, the prisoner dilemma, is not a zero sum game. However, as its maximum utility from any participant's point of view is when they "screw over" the other person when the other person is collaborating it tends to not generate much collaboration when only played once, especially in conditions where trust is lacking. I don't pretend to be an expert in game theory or its terminology, so I admit to stretching this analogy a bit.

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    Comments are not for extended discussion; this conversation has been moved to chat.
    – JJJ
    Commented Nov 24, 2021 at 19:42

Why would they? Suppose that we get 100 people together with the stated goal of building a house for X, and then 1 person walks off. Would that mean that the other 99 no longer want X to have a house?

While you are right that their non-participation puts an extra burden on those participating, the remainder still presumably want to participate.

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    To make the analogy even more apt, consider that the goal is to build a house for all 100 people. It's not just benefiting some third party here; it's benefiting the people doing the building themselves.
    – V2Blast
    Commented Nov 23, 2021 at 15:40
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    If 50 people walk off and make a lot of money by doing so, would the other 50 still want to stay? Commented Nov 23, 2021 at 16:10
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    @JonathanReez yes, because the alternative is homelessness. What good is the money if that 1 house is the only one that can be built?
    – Andrei
    Commented Nov 23, 2021 at 17:10
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    @Andrei if the other 50 walk off and the project fails anyway, there’s an incentive for the remaining 50 to give up too. Or conversely the threat of everyone giving up might induce others not to walk away. Commented Nov 23, 2021 at 17:59
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    @JonathanReez what is really the incentive for the remainers to give up? Incentive means getting better off. How are the remainers better off by increasing their own chance of homelessness, because the leavers took actions that also increased everyone's chance of homelessness? Considering the single goal of not being homeless, the only incentive there can exist for anything is reducing the chance of homelessness. Giving up, goes in the opposite way from the goal, regardless of what other 50 people may or may not do.
    – Andrei
    Commented Nov 23, 2021 at 19:23

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